1. Field of the Invention
The present invention relates to an image projection apparatus and a presentation system, and more specifically, to an image projection apparatus that converts image data to an optical image to project on a projection surface (screen) in an enlarged manner, and a presentation system to perform presentation, for example, pointing by irradiation light from an irradiation device (laser pointer and the like) on a projected image on the projection surface.
2. Description of the Related Art
Projectors project images such as characters and graphs on a screen (projection surface) in an enlarged manner, and therefore, are widely used in presentations to a number of people and the like. In such a presentation, a presenter (user) sometimes uses a laser pointer, an infrared laser pointer, or the like to point an image projected on a screen to make explanation easy to understand. However, in such a case, because a point that is pointed by the pointer moves as the hand operating the pointer moves, an exact pointed position can be unclear to people that are looking at the projected image. To solve the problem, a technique in which a point irradiated with an infrared laser pointer by a user is detected by a charge coupled device (CCD) camera that is equipped in a projector, and a pointer image is displayed at the same point (position) as this irradiation point (irradiation position) has been known (for example, Japanese Laid-open Patent Publication No. 11-271675).
However, when a laser pointer is used, if detection of a point irradiated by the laser pointer from a picture captured by a camera is considered similarly to Japanese Laid-open Patent Publication No. 11-271675, and if color and brightness of the projected picture are similar to color of the laser pointer, there is a possibility that the irradiation point of the laser pointer cannot be detected depending on a projected image. Particularly, for a digital light processing (DLP) (registered trademark) projector, there is a possibility that an irradiation point cannot be detected stably because of influence of leakage light from an adjacent filter segment in a different color in a color wheel.